Smrf.NodeXL.Visualization.Wpf.NodeXLControl.ZoomViaMouse C# (CSharp) Method

    ZoomViaMouse
    (
        MouseEventArgs e,
        Double dGraphZoomFactor
    )
    {
        Debug.Assert(e != null);
        Debug.Assert(dGraphZoomFactor > 0);
        AssertValid();

        // Do nothing if the drawing isn't in a stable state or a drag is in
        // progress.

        if ( this.IsLayingOutGraph || DragMightBeInProgress() )
        {
            return;
        }

        Double dGraphZoom = this.GraphZoom;

        Double dNewGraphZoom = dGraphZoom * dGraphZoomFactor;
        dNewGraphZoom = Math.Min(dNewGraphZoom, MaximumGraphZoom);
        dNewGraphZoom = Math.Max(dNewGraphZoom, MinimumGraphZoom);

        if (dNewGraphZoom == dGraphZoom)
        {
            return;
        }

        // Set the center of the zoom to the mouse position.  Note that the
        // mouse position is affected by the ScaleTransform used for this
        // control's layout transform and needs to be adjusted for this.

        Point oMousePosition = e.GetPosition(this);

        ScaleTransform oScaleTransformForRender = this.ScaleTransformForRender;
        oScaleTransformForRender.CenterX = oMousePosition.X;
        oScaleTransformForRender.CenterY = oMousePosition.Y;

        // Zoom the graph.

        SetGraphZoom(dNewGraphZoom, false);

        // That caused the point under the mouse to shift.  Adjust the
        // translation to shift the point back.

        Point oNewMousePosition = e.GetPosition(this);

        TranslateTransform oTranslateTransformForRender =
            this.TranslateTransformForRender;

        oTranslateTransformForRender.X +=
            (oNewMousePosition.X - oMousePosition.X) * dNewGraphZoom;

        oTranslateTransformForRender.Y +=
            (oNewMousePosition.Y - oMousePosition.Y) * dNewGraphZoom;

        LimitTranslation();
    }